Methods and apparatus for improved thermal performance and electromagnetic interference (EMI) shielding in integrated circuit (IC) packages is described. A die-up or die-down package includes a heat spreader cap defining a cavity, an IC die, and a leadframe. The leadframe includes a centrally located die attach pad, a plurality of leads, and a plurality of tie bars that couple the die attach pad to the leads. The IC die is mounted to the die attach pad. A planar rim portion of the cap that surrounds the cavity is coupled to the leadframe. The cap and the leadframe form an enclosure structure that substantially encloses the IC die, and shields EMI emanating from and radiating towards the IC die. The enclosure structure also dissipates heat generated by the IC die during operation.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An integrated circuit (IC) device package, comprising: an IC die; a leadframe, comprising: a centrally located die attach pad; a plurality of leads; and a plurality of tie bars that each couple the die attach pad to at least one of the leads; and a heat spreader cap defining a cavity, the cap comprising: a top, a sidewall coupled to the top, wherein the sidewall has an outer surface that opposes the cavity, and a rim that extends out from a segment of the outer surface of the sidewall, wherein the IC die is mounted to the die attach pad and wherein the cap and the leadframe form an enclosure structure that substantially encloses the IC die.
2. The package of claim 1 , wherein the package is in a die-up configuration.
3. The package of claim 1 , wherein the package is in a die-down configuration.
4. The package of claim 1 , wherein a tie bar couples the DAP to first and second leads.
5. The package of claim 1 , wherein the cap is in electrical and thermal contact with at least one lead.
6. The package of claim 1 , wherein the cap is electrical isolated from any of the plurality of leads.
7. The package of claim 1 , wherein at least a portion of the rim is coated with a dielectric material.
8. The package of claim 1 , wherein at least a portion of the leadframe coupled to the cap is coated with a dielectric material.
9. The package of claim 1 , wherein at least one of the plurality of tie bars is wider relative to others of the plurality of tie bars.
10. The package of claim 1 , wherein at least one of the plurality of leads is wider relative to others of the plurality of leads.
11. The package of claim 1 , wherein the cap is in electrical and thermal contact with at least one tie bar.
12. The package of claim 1 , wherein the plurality of tie bars and the plurality of leads are positioned in a first plane.
13. The package of claim 1 , wherein the plurality of tie bars are positioned in a first plane and the plurality of leads are positioned in a second plane.
14. The package of claim 1 , wherein the enclosure structure shields electromagnetic interference (EMI) emanating from the IC die, and shields the IC die from EMI radiating toward the IC die from outside the package.
15. The package of claim 1 , wherein the planar rim portion of the cap is coupled to the leadframe by a thermally and electrically conductive adhesive.
16. The package of claim 1 , further comprising: at least one electrically conductive plated area patterned on the leadframe in one or more areas in contact with the planar rim portion of the cap.
17. The package of claim 1 , wherein the cap is electrically insulated from the leadframe.
18. The package of claim 1 , wherein the cap is coupled to a ground potential.
19. The package of claim 1 , wherein the cap is coupled to a power potential.
20. The package of claim 1 , further comprising: at least one tab protruding from the rim; and at least one receptacle formed in a surface of the leadframe corresponding to the at least one tab, wherein the at least one tab is coupled with the at least one corresponding receptacle, whereby structural coupling of the cap to the leadframe is substantially improved.
21. The package of claim 20 , further comprising: a thermally and electrically conductive adhesive in the at least one receptacle.
22. The package of claim 20 , wherein the at least one tab has a conical, frustum, or laterally elongated shape.
23. The package of claim 20 , wherein a tab is positioned on a corner of the rim.
24. The package of claim 20 , wherein the at least one corresponding receptacle has an opening, indentation, or edge cutout configuration.
25. The package of claim 20 , wherein the at least one tab and the at least one corresponding receptacle are configured to facilitate coupling the cap to the leadframe in a predetermined orientation.
26. The package of claim 1 , further comprising: at least one electrically conductive plated area patterned on a surface of the leadframe in contact with one or more wirebonds.
27. The package of claim 1 , further comprising: at least one wirebond that couples at least one bond pad on a surface of the IC die to the leadframe, whereby the enclosure structure is coupled to an electrical potential.
28. The package of claim 27 , wherein the at least one bond pad is a ground pad, whereby the enclosure structure is coupled to a ground potential.
29. The package of claim 1 , further comprising: an encapsulating material that encapsulates the IC die.
30. The package of claim 29 , wherein the cap has an outer surface that coincides with the outer surface of the sidewall, wherein a first portion of the outer surface is covered by the encapsulating material, and wherein a second portion of the outer surface of the cap is not covered by the encapsulating material.
31. The package of claim 29 , wherein the encapsulating material further encapsulates an outer surface of the cap that coincides with the outer surface of the sidewall.
32. The package of claim 29 , wherein the encapsulating material further encapsulates at least a portion of the leadframe.
33. The package of claim 1 , wherein the cap has an outer surface that opposes the cavity, wherein the cap further comprises: at least one opening through the cap that is open at the outer surface and in the cavity.
34. The package of claim 33 , wherein the at least one opening through the cap is configured to facilitate flow of an encapsulating material into the cavity.
35. The package of claim 33 , wherein the at least one opening through the cap is configured to facilitate release of an air pressure inside of the enclosure structure.
36. The package of claim 1 , wherein the leads each have a shoulder bend portion along their lengths.
37. The package of claim 36 , wherein a peripheral dimension of the cap substantially coincides with a peripheral dimension of the leadframe at the shoulder bend of the leads.
38. The package of claim 36 , wherein a peripheral dimension of the cap is within a peripheral dimension of the leadframe at the shoulder bend of the leads.
39. The package of claim 36 , wherein a peripheral dimension of the cap exceeds a peripheral dimension of the leadframe at the lead shoulder bend of the leads.
40. The package of claim 1 , wherein the cap has an outer surface that opposes the cavity, further comprising: a heat sink coupled to the outer surface of the cap.
41. The package of claim 3 , wherein the cap has an outer surface that opposes the cavity, wherein the outer surface of the cap is configured to be coupled to a printed circuit board (PCB).
42. The package of claim 41 , wherein a thermally and electrically conductive adhesive is used to couple the cap to the PCB.
43. The package of claim 1 , wherein the sidewall makes an angle with the tie-bars that is less than 90 degrees.
44. An integrated circuit (IC) device package, comprising: a leadframe, comprising: a centrally located die attach pad; a plurality of leads; and a plurality of tie bars that each couple the die attach pad to at least one of the leads; an IC die coupled to the die attach pad; and a heat spreader cap defining a cavity, the cap comprising: a top, a rim, and a sidewall that couples the top to the rim, wherein the sidewall makes an angle with the tie-bars that is less than 90 degrees, wherein the IC die is mounted to the die attach pad and wherein the cap and the leadframe form an enclosure structure that substantially encloses the IC die.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
October 20, 2005
September 1, 2009
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